Financial Instruments and Fair Value Measurements (Summary of Carrying Values and Fair Values of Fixed Rate Debt) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity security with readily determinable fair value	$ 22.8	$ 15.4
Equity security without a readily determinable fair value	56.7	56.7
Net gains recognized during the period on equity securities	5.2	2.9
Less: Net gains recognized during the period on equity securities	0.0	0.0
Unrealized gains (losses) recognized during the reporting period on equity securities still held at the reporting date	5.2	2.9
Nonrecurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity Securities without readily determinable fair value, cumulative upward adjustment	3.4
Fixed Rate Debt [Member] \| Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed rate long-term debt	3,228.1	3,224.0
Fixed Rate Debt [Member] \| Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed rate long-term debt	$ 2,979.3	$ 2,803.6

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

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Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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